Circular Economy for Food Industry Waste: Development and Characterization of Spray-Dried Acid Whey Encapsulated in Millet Matrix

Abstract

Acid whey (AW) has become a significant challenge for the dairy industry because of the large quantity produced and the difficulty in further processing and economical disposal. This study investigated the feasibility of spray drying AW using millet flour as encapsulating wall material and examined the effect of different millet concentrations on the physio-functional properties of the newly developed acid whey millet (AWM) powders. The results showed that the millet flours had a neutralizing effect on AW, which aided the spray drying of AW by increasing the glass transition temperatures, thereby reducing the stickiness of the powders. Millet flours added to AW improved the yield, color, and reconstitution properties of AWM powders. AWM powders had a high concentration of phenolic compounds and exhibited high antioxidant activity. The results from this study indicate that millet flour can be used as a suitable wall material for spray drying AW and developing powders with potential applications as functional food ingredients.

A natural whitening alternative from upcycled food waste (acid whey) and underutilized grains (millet)

“…The b* values associated with the creamy color from the millet flours were decreased in the AWM powders. Similar L*, b*, and whiteness index values were reported for plain AW and AWM powders 21 . According to these results, AW encapsulated with millet improved powder functionality while retaining whiteness.…”

“…The input temperature, aspirator, feed pump rate, and gas flow rate were 160 °C, 90%, 15%, and 45%, respectively. These parameters were selected based on previously optimized parameters from prior experiments 21 . The obtained powders were stored at 4 °C in sealed glass jars until further analysis.…”

“…The novel AWM powder is rich in nutrients, minerals (such as P, K, Ca, Zn, and Cu), and antioxidants and could be extensively used in formulating functional foods and a mineral fortificant. Previous research 21 has revealed that the physical properties of the AWM powder show it to be a highly soluble, free-flowing powder with good functional properties. These findings suggest that AWM powder has a wide range of potential food and non-food applications in the food and pharmaceutical industries (Fig.…”

“…In previous studies 21 , we used Barnyard millet (Echinochloa species) and Little millet (Panicum species) flours as carrier materials to control and neutralize the lactic acid concentrations in AW and determined the physical properties of the spray dried powders. The resulting powders were white, with improved crystallization properties and enhanced powder yields.…”

“…The resulting powders were white, with improved crystallization properties and enhanced powder yields. The encapsulating effect of millet on AW was attributed to the molecular interactions between the proteins and the particle surface in the acid whey millet matrix (AWM) which resulted in the production of free-flowing powders with reduced stickiness, low hygroscopicity, and increased yield 21 . Figure 1.…”